High contrast liquid crystal display with adjustable white color point

Abstract

A display ( 1 ) for displaying an image and a method for driving such display is proposed. Therein, the display comprises: a background light ( 31 ), a first LCD panel ( 3 ) defining an array of pixel elements ( 13 ), a second LCD panel ( 5 ) defining an array of pixel elements ( 29 ) and a control unit ( 37 ) for driving the first and second LCD panels ( 3, 5 ). The second LCD panel ( 5 ) is a color display and is arranged between the first LCD panel ( 3 ) and the background light ( 31 ). The control unit ( 37 ) is adapted to control the second LCD panel ( 5 ) such that a white color point of the display ( 1 ) may be adjusted. Preferably, a diffuser ( 33 ) is arranged between the first display ( 3 ) and the second display ( 5 ). Accordingly, on the one hand, such display shows enhanced displaying properties such as an increased contrast and viewing angle, while, on the other hand, the white color point of the display can be adjusted as desired by using the control unit ( 37 ) for correspondingly controlling the second LCD panel ( 5 ) being preferably a low resolution color display.

1 . A display for displaying an image, the display comprising:
 a background light;   a first LCD panel defining an array of pixel elements;   a second LCD panel defining an array of pixel elements;
 a control unit for driving the first and second LCD panels; 
   wherein the second LCD panel is arranged between the first LCD panel and the background light;   wherein the second LCD panel is a color LCD panel; and   wherein the control unit is adapted to control the second LCD panel such that a white color point of the display may be adjusted.   
     
     
         2 . The display according to  claim 1 , wherein
 the display further includes sensor elements adapted to measure at least one of an intensity and a color of light transmitted through the second LCD panel.   
     
     
         3 . The display according to  claim 2 , wherein
 the control unit is adapted to control the second LCD panel such that a white color point of the display is adjusted automatically based on data measured by sensor elements.   
     
     
         4 . The display according to  claim 1 , wherein
 the control unit is adapted to control the second LCD panel such that a white color point of the display is adjusted locally with respect to positions within the two-dimensional array of pixel elements based on data measured by sensor elements at the respective positions.   
     
     
         5 . The display according to  claim 1 , wherein
 the control unit is adapted to control the second LCD panel such that a selectable region of the display is highlighted by adjusting the color of the background light transmitted through the second LCD display.   
     
     
         6 . The display according to  claim 1 , wherein
 the control unit is adapted to process image information of the image to be displayed such that a first portion of the image information is displayed on the first LCD panel and a second portion of the image information is displayed on the second LCD panel.   
     
     
         7 . The display according to  claim 6 , wherein
 the control unit is adapted to display the first portion of the image with a higher resolution than the second portion.   
     
     
         8 . The display according to  claim 1 , wherein
 the second LCD panel has a lower resolution than the first LCD panel.   
     
     
         9 . The display according to  claim 1 , further comprising a diffuser interposed between the first and second LCD panels. 
     
     
         10 . The display according to  claim 1 , wherein adjacent respective polarizers of the first and second LCD panels are aligned. 
     
     
         11 . A method for driving a display according to  claim 1 , the method comprising:
 processing image information of an image to be displayed and controlling the display such that a first portion of the image information is displayed on the first LCD panel and a second portion of the image information is displayed on the second LCD panel;   adjusting a white color point of the display by further processing the second portion of the image information.   
     
     
         12 . A computer program product which is adapted to perform the method according to  claim 11  when executed on a computer. 
     
     
         13 . A computer readable medium having a computer program product according to  claim 12  stored thereon.